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Author |
Török, S.; Braun, T.; Van Dyck, P.; Van Grieken, R. |
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Title |
Heterogeneity effects in direct XRF analysis of traces of heavy metals preconcentrated on polyurethane foam sorbents |
Type |
A1 Journal article |
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Year |
1986 |
Publication |
X-ray spectrometry |
Abbreviated Journal |
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Volume |
15 |
Issue |
1 |
Pages |
7-11 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abstract |
Trace amounts of heavy metals were preconcentrated on discs of polyurethane (PU) foam loaded with ammonium diethyldithiocarbamate (DDTC), to increase the sensitivity of XRF. Since the diameter of the cavities in the open-cell PU foams reaches 30300 μm, considerable heterogeneity effects might occur, which could reduce the accuracy of the method. The possible systematic error introduced by considering the sample to be homogeneous is calculated using the Berry et al. model. The calculations show that the underestimation of the absorption correction factor when considering the sample as being homogeneous is less than 2% for high-Z elements when the sample thickness is at least 2 mm. The detection limits are also around the minima for this thickness. |
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A1986AYN6000002 |
Publication Date |
2005-05-28 |
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ISSN |
0049-8246 |
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UA library record; WoS full record; WoS citing articles |
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no |
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Call Number |
UA @ admin @ c:irua:116488 |
Serial |
8030 |
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Permanent link to this record |
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Author |
Török, S.; Van Dyck, P.; Van Grieken, R. |
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Title |
Heterogeneity effects in direct X-ray fluorescence analysis of hair |
Type |
A1 Journal article |
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Year |
1984 |
Publication |
X-ray spectrometry |
Abbreviated Journal |
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Volume |
13 |
Issue |
1 |
Pages |
27-32 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abstract |
The methodology of direct hair analysis by energy-dispersive x-ray fluorescence was studied. The effect on the XRF result of having a non-homogeneous radial distribution of the analyte in a single hair strand and the macroscopic effects in a bundle of hairs were calculated to evaluate possible systematic errors. The detection limits were mapped as a function of the target thickness and surface fraction. It appeared that a 10 mg cm−2 sample thickness, i. e. a target with about four layers of hair strands, is recommended. The standard deviation of this simple direct analytical method is 619% for some important elements. Discrepancies with neutron activation analysis had a mean value of around 15%. About twelve elements can be determined simultaneously on a routine basis. |
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A1984SB70200004 |
Publication Date |
2005-05-28 |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0049-8246 |
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UA library record; WoS full record; WoS citing articles |
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no |
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Call Number |
UA @ admin @ c:irua:116485 |
Serial |
8029 |
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Author |
Markowicz, A.; Van Dyck, P.; Van Grieken, R. |
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Title |
Radiometric diameter concept and exact intensities for spherical particles in x-ray fluorescence analysis |
Type |
A1 Journal article |
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Year |
1980 |
Publication |
X-ray spectrometry |
Abbreviated Journal |
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Volume |
9 |
Issue |
2 |
Pages |
52-56 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abstract |
In X-ray fluorescence analysis the concept of radiometric diameter, d, is often introduced in considerations of the fluorescent intensity from a particulate sample. It represents the mean geometric path of the X-rays through one particle and is usually simply taken to be equal to the volume-to-area ratio of the particle. The effective radiometric path is, however, itself dependent on geometry and absorption effects. Rigorous calculations of the fluorescent intensity from a particle in the π and π/2 geometries were carried out to evaluate the errors involved. It appears that, for π geometry, the discrepancy between these exact results and the intensity calculated via the use of d does not exceed 5.2%. For the π/2 geometry, the errors are much larger and can amount to 50% in realistic cases of X-ray fluorescence analysis. These conclusions are also applicable to monolayers. The effective radiometric diameter approaches d only when absorption effects become negligible, but is smaller in other cases. |
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Wos |
A1980JN16500003 |
Publication Date |
2005-05-28 |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0049-8246 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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no |
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Call Number |
UA @ admin @ c:irua:116482 |
Serial |
8451 |
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Permanent link to this record |
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Author |
Van Dyck, P.; Markowicz, A.; Van Grieken, R. |
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Title |
Automatic absorption correction in x-ray fluorescence analysis of intermediate thickness samples using a dual external reference signal |
Type |
A1 Journal article |
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Year |
1980 |
Publication |
X-ray spectrometry |
Abbreviated Journal |
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Volume |
9 |
Issue |
2 |
Pages |
70-76 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abstract |
A method has been investigated which allows calculations from the X-ray fluorescence spectra of the absorption coefficients at any energy for any sample, without any additional measurement. Use is made of the ratio of the characteristic X-ray signals from a Zr wire positioned in front of the sample and from a Pd foil placed behind the sample, both in a fixed geometry. From the experimentally measured absorption coefficient at the Pd L energy (2.9 keV), the coefficients for higher energies are calculated. By the use of an iterative computer routine in which corrections for the enhancement of the Pd foil by the sample are also included, an accuracy of 2% or better on the absorption coefficient determination can be reached for homogenous samples in one measurement. Grain-size and heterogeneity effects induce inaccuracies on the absorption coefficient determinations which might well reach 20% for particulate samples like intermediate thickness deposits of geological materials. This approach thus has the same limitations as the classical transmission method for such heterogeneous samples. |
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Wos |
A1980JN16500007 |
Publication Date |
2005-05-28 |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0049-8246 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Open Access |
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no |
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Call Number |
UA @ admin @ c:irua:116483 |
Serial |
7541 |
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Permanent link to this record |
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Author |
Storms, H.; Van Dyck, P.; Van Grieken, R.; Maenhaut, W. |
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Title |
Electron microprobe observations of recrystallization affecting PIXE-analysis of marine aerosol deposits |
Type |
A1 Journal article |
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Year |
1985 |
Publication |
Journal of trace and microprobe techniques |
Abbreviated Journal |
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Volume |
2 |
Issue |
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Pages |
103-117 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0733-4680; 1532-2270 |
ISBN |
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UA library record |
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Open Access |
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Approved |
no |
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Call Number |
UA @ admin @ c:irua:116718 |
Serial |
7871 |
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Permanent link to this record |
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Author |
Van Dyck, P.; Van Grieken, R. |
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Title |
Automated matrix-correction of line ratios in energy-dispersive x-ray fluorescence spectrum deconvolution |
Type |
A1 Journal article |
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Year |
1983 |
Publication |
X-ray spectrometry |
Abbreviated Journal |
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Volume |
12 |
Issue |
3 |
Pages |
111-114 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abstract |
Most computer XRF-spectrum deconvolution routines make use of fixed intensity ratios for the lines from one element. The magnitude of the error that fixed ratios imply has been quantitatively evaluated for samples with a varible thickness or matrix. A procedure for routinely adapting the line ratios according to the matrix effect in every sample (by making use of the matrix information present in the scatter peaks) enhances the accuracy of the spectrum evaluation. |
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Wos |
A1983RA69700004 |
Publication Date |
2005-05-28 |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0049-8246 |
ISBN |
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Additional Links |
UA library record; WoS full record |
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Impact Factor |
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Open Access |
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Notes |
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Approved |
no |
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Call Number |
UA @ admin @ c:irua:116484 |
Serial |
7539 |
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Permanent link to this record |
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Author |
Van Grieken, R.; Robberecht, H.; Shani, J.; Van Dyck, P.; Vos, L. |
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Title |
Energy-dispersive X-ray fluorescence for direct trace analysis of biomedical and environmental samples |
Type |
H3 Book chapter |
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Year |
1982 |
Publication |
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Abbreviated Journal |
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Volume |
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Issue |
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Pages |
159-178
T2 - X-ray fluorescence (XRF and PIXE) in |
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Keywords |
H3 Book chapter; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Additional Links |
UA library record |
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Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
no |
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Call Number |
UA @ admin @ c:irua:117485 |
Serial |
7904 |
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Permanent link to this record |
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Author |
Vos, L.; Robberecht, H.; Van Dyck, P.; Van Grieken, R. |
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Title |
Multi-element analysis of urine by energy-dispersive x-ray fluorescence spectrometry |
Type |
A1 Journal article |
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Year |
1981 |
Publication |
Analytica chimica acta |
Abbreviated Journal |
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Volume |
130 |
Issue |
1 |
Pages |
167-175 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abstract |
For multi-element analysis of human urine, 25-ml samples doped with yttrium as internal standard are evaporated gently and then ashed up to 460°C overnight. The residue is pelletized and analysed by energy-dispersive x-ray fluorescence. Acid addition to facilitate the digestion is not mandatory. Recoveries are nearly quantitative for traces of Fe, Ni, Cu, Zn and Sr, to a lesser extent for lead, but not for arsenic or selenium. The standard deviation per measurement is typically around 6%. The detection limits are such that some 10 elements can be determined simultaneously in normal urine, and possibly more in cases of importance to toxicology or industrial hygiene. |
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A1981ME98900017 |
Publication Date |
2002-07-25 |
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Abbreviated Series Title |
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Edition |
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ISSN |
0003-2670; 1873-4324 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Open Access |
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Notes |
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Approved |
no |
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Call Number |
UA @ admin @ c:irua:116439 |
Serial |
8285 |
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Permanent link to this record |
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Author |
Van Dyck, P.; Markowicz, A.; Van Grieken, R. |
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Title |
Influence of sample thickness, excitation energy and geometry on particle size effects in XRF |
Type |
A1 Journal article |
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Year |
1985 |
Publication |
X-ray spectrometry |
Abbreviated Journal |
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Volume |
14 |
Issue |
4 |
Pages |
183-187 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abstract |
Expressions are presented for calculating the matrix effect and the pure particle size effect in the XRF analysis of particulate samples with a discrete particle size. The equations are based on the absorption-weighted radiometric diameter concept. Two excitationdetection geometries are considered, with the angles between the sample plane and both the incident and emerging radiation being either 90° (π geometry) or 45° (π/2 geometry). Calculations were made for different sample loadings and exciting radiation energies. The influence of these parameters on the matrix and pure particle size effects is shown. From the results, it is possible to predict the performances of alternative experimental correction procedures for the particle size effect, involving dual measurements at different excitation energies or in different excitationdetection geometries. |
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Wos |
A1985ATB6100007 |
Publication Date |
2005-05-28 |
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Series Editor |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0049-8246 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Open Access |
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Notes |
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Approved |
no |
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Call Number |
UA @ admin @ c:irua:116486 |
Serial |
8097 |
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Permanent link to this record |
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Author |
Van Dyck, P.; Török, S.; Van Grieken, R. |
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Title |
Monte Carlo simulation of backscattered peaks in secondary target energy-dispersive X-ray spectra |
Type |
A1 Journal article |
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Year |
1986 |
Publication |
X-ray spectrometry |
Abbreviated Journal |
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Volume |
15 |
Issue |
4 |
Pages |
231-238 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abstract |
A Monte Carlo simulation has been developed to describe the incoherent and coherent scatter processes for the complex geometry of a secondary target energy-dispersive x-ray fluorescence system. Photons are followed from the x-ray tube anode until the detection of scattered secondary target photons in the active Si layer of the detector. The program quantitatively shows the broadening of the incoherent scatter peak with increasing atomic number, and it models the incoherent peak shape adequately. The incoherent-to-coherent scatter intensity ratios obtained differ by 1030% from the theoretical values, while their dependence on the sample atomic number corresponds to that expected from theory. |
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A1986E535600001 |
Publication Date |
2005-05-28 |
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Series Editor |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0049-8246 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Times cited |
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Open Access |
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Notes |
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Approved |
no |
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Call Number |
UA @ admin @ c:irua:113612 |
Serial |
8280 |
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Permanent link to this record |
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Author |
Van Dyck, P.; Van Grieken, R. |
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Title |
Automated energy-dispersive X-ray fluorescence analysis for diverse environmental samples |
Type |
H3 Book chapter |
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Year |
1982 |
Publication |
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Abbreviated Journal |
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Volume |
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Issue |
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Pages |
315-324
T2 - Analytical techniques in environmenta |
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Keywords |
H3 Book chapter; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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UA library record |
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Open Access |
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Approved |
no |
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Call Number |
UA @ admin @ c:irua:117484 |
Serial |
7536 |
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Permanent link to this record |
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Author |
Van Dyck, P.; Storms, H.; Van Grieken, R. |
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Title |
Automated quantitative electron-microprobe analysis of particulate material |
Type |
A1 Journal article |
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Year |
1984 |
Publication |
Journal de physique |
Abbreviated Journal |
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Volume |
45 |
Issue |
C:2 |
Pages |
781-784 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abstract |
An automated electron microprobe, equipped with an energy-dispersive X-ray spectrometer and an additional backscattered electron signal digitalization system, can allow rapid sizing and major element analysis on numerous particles. A software package has been developed to exploit the particle size and shape information to achieve quantitative analysis of single particles, and to compare the performance of the different matrix correction procedures. |
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Wos |
A1984SQ01400181 |
Publication Date |
2007-08-21 |
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Abbreviated Series Title |
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Series Volume |
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Edition |
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ISSN |
0302-0738 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Open Access |
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Notes |
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Approved |
no |
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Call Number |
UA @ admin @ c:irua:113620 |
Serial |
7540 |
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Permanent link to this record |
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Author |
Van Dyck, P.M.; Török, S.B.; Van Grieken, R.E. |
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Title |
Enhancement effect in X-ray fluorescence analysis of environmental samples of medium thickness |
Type |
A1 Journal article |
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Year |
1986 |
Publication |
Analytical chemistry |
Abbreviated Journal |
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Volume |
58 |
Issue |
8 |
Pages |
1761-1766 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Wos |
A1986C955500040 |
Publication Date |
2005-03-08 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0003-2700; 5206-882x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Times cited |
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Open Access |
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Notes |
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Approved |
no |
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Call Number |
UA @ admin @ c:irua:116522 |
Serial |
7915 |
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Permanent link to this record |
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Author |
Van Dyck, P.M.; Van Grieken, R.E. |
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Title |
Absorption correction via scattered radiation in energy-dispersive X-ray fluorescence analysis for samples of variable composition and thickness |
Type |
A1 Journal article |
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Year |
1980 |
Publication |
Analytical chemistry |
Abbreviated Journal |
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Volume |
52 |
Issue |
12 |
Pages |
1859-1864 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Language |
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Wos |
A1980KJ65700021 |
Publication Date |
2005-03-08 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0003-2700; 5206-882x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
no |
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Call Number |
UA @ admin @ c:irua:116516 |
Serial |
7410 |
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Permanent link to this record |